Protective apparatus for electrical instruments.



J. T. GREENE. PROTECTIVE APPARATUS FOR ELECTRICAL INSTRUMENTS.

APPLICATION FILED MAR. 2. I914.

Patentd Apr. 11, 1916;

2 SHEETS-SHEET I.

A TTORNE Y5.

I. I. GREENE. PROTECTIVE APPARATUS FOR ELECTRICAL INSTRUMENTS.

APPLICATION FILED MAR- 2. 1.914- I Patented Apr. 11, 1916.

2 suns-sneer 2.

STATES PATENT QFFICE. .r'onn'r. ennnnn, or rornnojinro, nssrenon To run NATIONAL nrlnoraic SPECIALTY company, or TOLEDO, 01110, A CORPORATION or 01110.

Specification of Letters Patent.

Patented Apr. 11, 1916.

Application filed March 2, 1914. Serial No. 822,009.

tus for electrical instruments, and the invention has for a primary object to provide an electrical instrument with protective appa-.

ratus consisting of a plurality of devices which become operative under somewhat different conditions to safe-guard the instrument against abnormal currents and disturban'ces of various sorts due, for example,

to. lightning discharges and" crosses with high power circuits, which devices arecon- 'structed and arranged so that one. protects the other andso that in case one should become inoperative .theaothe r or others will give a measure of protection, at least, to the instrument with which said apparatus is associated.

.A further object of theinvention is to,

provide an' apparatus of this character which will be compact in form, economical to. manufacture,conveniently installed, and

so constructed thatthe parts requiring oc casional renewal may be easily replaced without disturbing the other parts of the apparatus.

The invention hasfor'further objects 'such other new and improved constructions, ar rangementsand devices relating to the protection of electrical instruments from abnormalcurrents and disturbances as will be hereinafter described and claimed.

The invention is shown 1n the accompany ing drawings as embod1ed in a preferred form of apparatus.

In the drawings Figure 1 is a plan view of the apparatus; Fig. 2,7a side elevation of the same; Fig. 3, a sectionalview taken on line 3--3 of Fig. 1; Fig. .4, a fragmentary sectional view on line of Fig. 1, and

' Fig. 5, a diagram to show the electrical connections.

Like characters of reference designate, like parts in the'several figures of the drawings. Referring'to the drawings, 10 designates a base which may be permanently affixed to a switch-board signal box or other support,

designated 11, by'the bolts 12. The par- T, GREENE, ah

trically connected therewith by the metal strip 16, is a spring clip or jack 17. Similarly a spring clip or. jack 18 is mounted on the base near the terminal, 15 and electris cally connected therewith by means of-the metal strip 19, 19. A similar pair of clips 17, 18 areassociated with terminals 141,

15'. These clips-are adapted to receive fuses 20, 20 of any suitable construction.

The grounded wire 13 is carried .up through a groove 21 in the side of the base member 10 to a binding post'22 arranged between the fuses 20, 20.. The aerials 23, 23: may be connected with either pairof terminals 14, 14, or 15, 15. I have shown I on the base adjacent terminal 14, "and electhem as connected with.the-terminals 14,"

14, the instruments A, A being connected with the other pair of terminals 15, 15 by wires designated 21, 24'.

"25 designates the evacuated bulb of a vacuuinarresterhaving two line wire elec-' trodes 26, '26 and a single ground electrode 27. The bulb 25 is mounted on a base member 28 detachably secured to the base 10 by means providing electrical connections between electrodes 26, 26', 27 and-binding posts 15,, 15, 22, as follows: The leading-in wires 29, 29 for electrodes 26, 26,are connected with Ushaped clips 30,. 30 secured "to the base member 28 by screws 31. These clips are adapted to project: into spring I jacks 32, 32 fitted into recesses in the base 10 secured to the base by screwsv 33 and electrically connected with the binding posts 15, 15. respectively, by the angular metal strips 31. The leading-in wire 35 ofythe ground electrode 27 is connected with a strip 36 secured to the base member28 screw 37 and formed at its outer end with a slot 38 for a'bolt 39 on the baselO, Themechanical and electrical connectio'nsvare completed by nuts 10 and bv a wlre 11 connecting bolt 39 to the binding post 22.

mounted so that they may be turned on the.

bolts 43 makes it possible to employ the air gaps or not as may be desirable in a particular case, and, when this auxiliary protection is desirable adjusted. s

The operation of theapparatus above described is as follows: If the disturbance on one of the aerials, say wire 23, is of short duration, even though it may have a very high voltage, such for example as is produced by the ordinary lightning discharge, 2 the current will pass through the fuse without burning it out but will be grounded by the vacuum arrester. If the abnormal charge be of considerable duration, for example as might occur from a cross between line 23 and a trolley -wire or other high power circuit, and this be allowed to go to the vacuum arrester, the result would be likely to be the burning out of the arrester resulting either in a permanent ground through the arrester or the destruction of the instrument intended to be protected. Under these circumstances, however, with the arrangement I have shown, fuse 20 will burn out so that both the instrument and the vacuum arrester will be saved. If desired 3 the wires 23, 23 may beconnected with binding posts 15, 1-5 and the wires 24, 24' with binding posts 14, 14.. In this arrangement, however, the vacuum arrester would 40 not be as well protected.- s

It will be seen that the apparatus above "described. is extremely compact. Each unit serves two circuits through a single ground. By multiplying the units and placing them side by side on the switch-board or other support, a large number of instruments can be protected by apparatus which occupies but little space. The parts likely to require occasional replacement, the fuses and .the v vacuum arrester, may be replaced and renewed Without disturbing the wiring or other parts of the apparatus. To remove the vacuum arrester it is only'necessary to unscrew nuts 40 and detach the base members 28 from the base 10 by pulling clips 30, '30" from the spring jacks, which they normally engage.

A further protection to the instrument is afforded by the air gap provided by elements 42, 45.

ment 42 is intended to give the gap between it and the grounded element 45 a resistance higher than the normal resistance of the vacuum a The air a however becomes a5 efiective to ground an abnormal charge if,

permits the gaps to be The adjustment of the elefor any reason, the vacuum arrester fails to perform this function.

While I have' 'described my invention in appended hereto.

I claim: I 1. In protective apparatus for an electrically operated instrument, the combination with a fixed base member, of a pair of line wire term nals on said base member, a pair of fused clips connected with said terminals, respectively, a ground line-terminal, an adjustable element. connected with one of said clips which projects close to but Without touching said ground wire terminal, an arrester comprising an evacuated vessel andspaced electrodes therein, a base member on which said arrester is mounted, and means for detachably securing this base'member to the fixed base member, which means provides electrical connections between said electrodes and the terminals on said fixed base member.

2. In protective apparatus for an electrically 0perated-instrument, the combination with a fixed base member, ofa pair of line wire terminals on said base member, a pair of fused clips connected with said terminals, respectively, a ground-wire terminal, an arrester comprising an evacuated vessel and spaced electrodes, a base member on which said. arrester is mounted, and means for detachably securing the last mentioned base member to said fixed member, which means provides electrical connections between said electrodes and the terminals on said fixed base member.

3. In protective apparatus for an electrically operated instrument, the combination -with-'a fixed base member, of two pairs of line wire term nals on said base member, two

pairs of fuse clips electrically connected with said pairs of terminals, respectively, a single ground wire terminal, an arrester comprising an' evacuated vessel having mounted therein a pair of line electrodes and asingle mounted electrode, a base member on which said arrester is mounted, and means for de-' tachably securing said last mentioned base 'member to the fixed base member, which -means provides electrical connections between said electrodes and theterminals on said fixed base member. 4. In protective apparatus for an electrically operated instrument, the combination with a fixed base member, of two pairs of line wire terminals on said base-member, two pairs of fuse clips electrically connected with said pairs of terminals,respectively, a single ground wire terminal, and arreste compris- Correction in" Letters Patent No. 1,178,713;

; said arrester is mounted, means for detachably securing said last mentioned base memberv to the fixed base member, which means provides electrical connections beterminalstween said electrodes and the on said fixed base member, sparking points connected each with one of each pair of fuse clips and revolubly mounted on said fixed base member, and an angular plate associated with the grounded terminal arranged so that the sparking points come into proximity without touching the corners thereof.

5. In protective-apparatus for an. electriin Protective Apparatus for the words and arrested the casein the Patent Ofiicei [sun] Signed and sealed this 23d day of May, A. D. 1916.

cally operated instrument, the combination with a base member, of two pairs of line wire terminals on said base member, two pairs of fused clips electrically connected with said pairs of terminals respectively, a single ing an evacuated vessel having, mounted therein a pair of line electrodes and a single ground wire terminal, an arrester comprisgrounded electrode, and means for detachably securing said arresterto the base mem-- her, which means prcvides electrical connections between said electrodes, and their respective terminals on saidbase member. JOHN T. GREENE. Witnesses:

, P. H. CHAPMAN,

M. J. OGORMAN.

It is hereby certified that in Letters Patent No. 1,178,713, granted April'll, 1916, upon the applicationof John T. Greene, of Toledo, Qhio, for an improvement Electrical Instruments, an error appears in the printed specification requiring correction as follows: Page line 130, claim 4, for

readsdn arrester; and thatthe said Letters Patent should -be read with this correction therein that thesame may conform to the record of VJ: T. NEWTON,

Acting Commissioner of Patents. 

